#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;

const int N = 100010;

typedef pair<int, int> PII;

int n;
vector<PII> segs;

void merge(vector<PII> &segs){
    vector<PII> res;
    sort(segs.begin(), segs.end());
    int st = -2e9, ed = -2e9;
    for(auto seg : segs){
        if(ed < seg.first){
            if(st != -2e9) res.push_back({st, ed});
            st = seg.first, ed = seg.second;
        }
        else ed = max(ed, seg.second);
    }
    if(st != -2e9) res.push_back({st, ed});
    segs = res;
}

int main(){
    cin >> n;
    for(int i = 0; i < n; i ++){
        int l, r;
        cin >> l >> r;
        segs.push_back({l, r});
    }
    merge(segs);
    cout << segs.size() << endl;
    return 0;
}